PhreeqcUsers Discussion Forum

Processes => Dissolution and precipitation => Topic started by: Alexey on September 26, 2015, 10:36:32 PM

Title: Equations of mineral dissolution
Post by: Alexey on September 26, 2015, 10:36:32 PM
Some papers may consider equations of mineral dissolution different from used in PHREEQC. For example llnl.dat attributes for albite:
NaAlSi3O8 + 4 H+  =  + Al+++ + Na+ + 2 H2O + 3 SiO2
I can find 2 other variants:
NaAlSi3O8 + H+ + 7H2O = Al(OH)3 + 3H4SiO4 + Na+
NaAlSi3O8 + 2 H+  =  + Al+++ + Na+ + 2 OH- + 3 SiO2
May I use those reactions with recalculated pK? Or they are not applicable?
Title: Re: Equations of mineral dissolution
Post by: dlparkhurst on September 26, 2015, 11:24:04 PM
You can use any equation you want as long as the log K is appropriate to the reaction, and the aqueous species used in the reaction are defined. The equations you have are written to SiO2(aq), which is present in the llnl.dat database, but not in any of the other databases.